Andrew Coppin wrote:
> OK, these still blow me away...

Well, thanks :)

> I can't believe how much detail they have in them... It must take
> years to render then,

Computing the photon maps is the slow stage. I've now decreased the
photon spacing to 0.002, and building the photon map took 8 h 24 min
with a 2.4 GHz P4, but the same map is then used for all the images
of this set. The size of the present photon file is 516 Mb.

Rendering the individual images at 1024x683 takes between one and two
hours, which is reasonable, but then I render quite many images at
either 3000x2000 or 7620x5080 to be printed at 254 dpi (100 dots/cm).
Even on screen, the images look much better if they are rendered at
a higher resolution and then scaled down with GIMP, perhaps adding
a tiny amount of blur before scaling down in order to get rid of some
of the last remnants of jiggies and surface noise, see attached images.
The upper parts are crops from images rendered at 1024x683, the lower
parts are from the same images rendered at 3000x2000, with a minimum
amount of gaussian noise added and scaled down to 1023x683.

At higher resolutions, the decreased photon spacing also makes a
difference, as you can see from the attached comparison. The upper part
has a photon spacing of 0.01, the middle part 0.003 and the lower part
0.002. At lower resolutions the differences between the last two are
quite subtle, there is just a sense of a kind of heightened definition
and realism.

 > never mind how long it must have taken to model in the first place...

The modelling didn't take too long. The harpsichord took about four full
days, but at that time I had just started and didn't have the foggiest
idea about how to organize the modelling, I had a slower computer and
was working via a slow modem line so I spent quite a lot of time just
impatiently waiting to see the next test image to appear on the screen.
There are about 2,500 parts in the harpsichord, e.g. 55 parts for each
of the 45 keys (i.e. the key with the associated action and string).
For details, see

   http://www.animal.helsinki.fi/people/vilva/gallery/

I used perhaps three evenings designing the string instrument, but all
the rest is much simpler.

Now I spend most of my time thinking about the visual aspects, trying
to find simple ways of making the images look somewhat less artificial
even though I'm not trying to reproduce reality -- my ideal is an image
which somehow feels too real to be unreal although you know it cannot be
real :)

    Veijo

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